#Count All Objects with Label `env=prod` Across Types
kubectl get all --all-namespaces -l env=prod
#To Count the Total Number of These Resources
kubectl get all --all-namespaces -l env=prod --no-headers | wc -l
# All in One (Optional Script-ish Bash)
(
kubectl get all --all-namespaces -l env=prod --no-headers
kubectl get nodes -l env=prod --no-headers
kubectl get pv -l env=prod --no-headers
) | wc -l
A key difference between Field Selectors and Label Selectors in Kubernetes is their focus and usage:
Field Selector (-field-selector): This allows you to filter Kubernetes resources based on their specific fields. For example, if you want to filter pods by a specific condition like their phase (e.g., running, pending), you can use a command like:
kubectl get pods --field-selector=status.phase=Running
Here, you're filtering based on a specific field's value. Field selectors support conditions like equal (=), double equal (==), and not equal (!=) for different fields of the resources.
Label Selector (l or -selector): This is used to filter resources based on user-defined labels that you can attach to the resources. For example, if you have labeled some pods with app=frontend, you can select those pods using:
kubectl get pods -l app=frontend
The -l flag filters based on the labels' key-value pairs, allowing for flexible grouping and selection of resources.
In summary, use Field Selectors for filtering based on intrinsic properties of the resource, such as its status or creation time, whereas Label Selectors are more about the custom tags you assign to the resources for identification and management purposes. This differentiation helps in organizing resources effectively in large Kubernetes environments. If you have any further questions or need clarification on a specific type of selector, feel free to ask!